In this disclosure, the term ‘tire’ denotes a pneumatic tire that is air-tight and mounted in the rim bed of the rim. When used, or during a measuring operation, the tire is filled with air at prescribed operating pressure provided by tire or vehicle manufacturers.
The term ‘rim’ refers to the part of a wheel that is made of metal, in particular aluminium, steel, or other alloy, and to which a pneumatic tire, usually made of rubber, is attached. The rim includes a peripherally extending rim bed to which the tire is attached, and a wheel disc portion within the peripherally extending rim bed. That wheel disc portion may have apertures or no aperture at all. The wheel disc may also be formed from spokes.
Geometrical non-uniformities in the tire and rim, such as uneven weight distribution or construction, usually cause problems in operation of vehicle wheels. Known methods for determining and minimizing the effects of non-uniformities (called matching) involve steps for ascertaining a highest point of the runout of the tire, and a lowest point of the runout of the rim, or vice-versa. The effects of non-uniformities of vehicle wheels can be minimized by rotating the tire relative to the rim to a carefully selected position, such that the resulting effects caused by the non-uniformities of the tire and the wheel are offset. For example, non-uniformities of a vehicle wheel may be minimized or cancelled out by rotating the tire relative to the rim to a selected position such that the highest point of the runout of the tire coincides with a position at which the lowest point the rim runout rests.
It is noted that the rotation smoothness of a vehicle wheel, in particular a motor vehicle wheel, is affected not only by forces caused by geometrical non-uniformities of the wheel, but also by centrifugal forces resulting from wheel imbalance. It is known to compensate such imbalance effects using a mass equalization procedure by, for example, attaching balancing weights to the wheel. However, such compensation process only addresses the effects coming from the centrifugal forces, and does not address the effects caused by the geometrical non-uniformities of the vehicle wheel.
Therefore, there is a need to provide an integrated method for matching vehicle wheels to improve the operation smoothness of vehicle wheels. There is another need for a convenient procedure that addresses both the effects caused by the geometrical non-uniformities and the imbalance of the vehicle wheel.